Additional staining for cytokeratin 5/6 (KRT5/6), epidermal growth factor receptor (EGFR) and Ki-67 has also been used as a surrogate for gene expression profiling to allocate tumours to luminal A, luminal B, HER2 or basal-like molecular subtypes (Blows et al., 2010). This evidence concerns the gene MKI67 and neoplasm.